Quote:
Originally Posted by nakisawame
I'd love to do some bargain hunting and look second hand - I've already scanned ebay a few times over the past month or so, problem being my lack of knowledge. All I see are a bunch of numbers with some fancy words and so find it hard to judge what's a good option! If anyone could enlighten me on what I should be looking out for (I hear a lot of aperture, refractor, reflector and 60mm/100mm etc) no idea how to really process any of it.
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Hannah
Given above quote, I think it is important that you learn a little more about scopes before jumping in. Given such a limited budget, it is important that you get something that you will be happy with and not feel you wasted your money.
The first thing to remember with scopes is that most of the time you get what you pay for. The other thing to bear in mind is there is no such thing as a good allround telescope. Every type has its shortcomings and strength and learning more so you understand those factors will help you to reach a decision.
To start the ball rolling I will dicuss some of the terms you may be struggling with
1. Aperture
This is the diameter of the lense or mirror that collects the light in a scope. Simply put the bigger the better! the 2 scope syou mentioned in your first post both have 76mm apertures, or approx 3 inches. They are very small. Only the brightest objects will be visible in these scope bcause they simply don't collect enough light. Increasing aperture has a dramatic effect. A six inch scope colect 4 times as much light as a 3 inch and a 12" get 16 times as much. Thats why we say aperture rules!
2. Refractor. This is a telescope that uses lenses to collect light. Usually the eyepiece(what you look through) is at the end of a tube with a bigger lense (objective) at the other. The size of the big lense or objective is the aperture.
3. Reflector. This is a scope that uses a mirror to collect the light. The commonest form is a Newtonion which has the main mirror (objective) at the bottom of a tube and the eyepiece off to one side of the top of the tube. Both of the scope you mentioned are in this style. The sie of the main mirror is the aperture.
I will continue this post shortly with some more info on focal length and eyepieces
Malcolm